Sequential activation of ground pads reduces skin heating during radiofrequency ablation: Initial in vivo porcine results

Purpose: Radiofrequency (RF) ablation is a common treatment modality for inoperable liver cancer. Skin burns below ground pads during RF ablations are increasingly prevalent, hindering the development of higher-power RF generators capable of creating larger ablation zones. Materials and Methods: 9 RF ablations (n = 4 simultaneous, n = 5 sequential) were performed with 300 W for 12 min via two internally cooled cluster electrodes placed in the gluteus maximus of domestic swine. Three ground pads placed on the animal´s abdomen were activated either simultaneously, or sequentially where activation timing was adjusted to equilibrate skin temperature below each pad. Temperature rise at each pad was compared. Ablation zone dimensions were determined via MRI. Results: Maximum temperature rise was significantly higher with simultaneous activation than with sequential activation (21.4 vs 8.1degC, p < 0.01). Ablation zone diameters during simultaneous and sequential activation were 6.9 plusmn 0.3 and 5.6 plusmn 0.3.,respectively. Conclusion: Sequential activation of multiple ground pads resulted in significantly lower skin temperatures during high-power RF ablation.